Certain cylinder/piston assemblies must be purged of any gas entrapped within in order to operate effectively. For example, a vehicle master brake cylinder must be purged of any entrapped gas in order for the braking system of a vehicle to operate in an effective and safe manner. Typically, a vehicle master brake cylinder comprises a housing having an interior cylinder, a primary piston movably mounted within the cylinder, and a brake fluid reservoir containing brake fluid in communication with the cylinder to keep the cylinder filled with brake fluid.
Various apparatus exist for purging or bleeding gas from cylinder/piston assemblies, but these apparatus suffer from certain drawbacks. For instance, these bleeding apparatus are complex, bulky and costly. Consequently, they are difficult and awkward to operate and require an inordinate amount of servicing. Moreover, these previous bleeding apparatus are unreliable in properly bleeding the gas from the cylinder/piston assembly.
One known bleeding apparatus comprises a support means upon which the cylinder/piston assembly is mounted for bleeding and adjacent to the support means a pivotally mounted lever that is connected to a push rod. By pulling down on the lever, the push rod engages the primary piston through an access opening and pushes the piston into the cylinder, thereby forcing entrapped gas from the cylinder.
This bleeding apparatus, although an improvement over earlier bleeding apparatus, remains bulky, costly and inconvenient particularly when an uncommon cylinder/piston assembly is being bled because the support means will not readily support the uncommon assembly. Moreover, the push rod of this known bleeding apparatus requires realignment when used with an uncommon cylinder/piston assembly since the push rod will not line up with the primary piston of the cylinder/piston assembly. Furthermore, this apparatus is susceptible to over stroking or under stroking the piston. Over stroking in bleeding a cylinder can cause damage to piston seals and allow leaking of fluid from the cylinder/piston assembly, and under stroking can lead to the ineffective or inefficient bleeding of gas from the cylinder. Thus, there is a need for a bleeder tool that is inexpensive, flexible, efficient and effectively bleeds air from any cylinder/piston assemblies.